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Biomedical subjects

P Moens

Publications and source records attributed to P Moens.

At least 19 recordsLinked to original sources
PubMed2005

Reduced recombination associated with the production of aneuploid sperm in an infertile man: a case report.

Studies using gene-linkage analysis have suggested that abnormal recombination during meiosis may lead to the production of aneuploid gametes; however, there is little direct evidence of a link between the two in human males. We analysed spermatocytes in the pachytene stage from a man with extremely high aneuploidy rates in his sperm. Testicular tissue specimens of the infertile man and two vasectomy reversals were processed with immuofluorescent techniques to visualize synaptonemal complex and recombination foci and fluorescent in situ hybridization on spermatocytes and sperm with probes for chromosomes 13, 21, 18, X and Y. We observed no recombination between sex chromosomes in the infertile man, while in two controls, we observed recombination rates of 79.3 and 81.0% between the sex chromosomes. This was associated with a total sex aneuploidy rate of 41.61% in testicular sperm of the infertile man (0.44 and 0.62% in two controls). Recombination on chromosome 21 was reduced in the infertile man, with 10.62% of spermatocytes showing no recombination (0 and 1.67% in two controls), as well as chromosome 13, with 53.98% having < or =1 recombination foci (22.05 and 21.67% in two controls). This was associated with increased aneuploidy for those chromosomes. Chromosome 18 aneuploidy was slightly increased, although there was no apparent decrease in recombination. These results provide the first evidence of both recombination and non-disjunction abnormalities in the same individual. This is also the only reported case of an infertile man who shows no recombination between the sex chromosomes, despite the formation of the sex body.

Abortion, Spontaneous↗
PubMed2005

An active shape model for the reconstruction of scoliotic deformities from back shape data.

OBJECTIVE: The objective of the present study is to improve the accuracy and reliability of the spinal midline reconstructions in scoliosis from back shape data. Design. An active shape model which covers the variety of scoliotic curves with a minimum of adjustable parameters is designed for the reconstruction of the spinal midline based on rasterstereographic back surface measurements. BACKGROUND: To reduce the number of X-rays needed for patients with a scoliosis, an automatic method was developed for the reconstruction of spinal deformities from back shape data. METHODS: 264 digital X-rays of 264 patients with scoliosis were used as a training set. By examining the statistics of the vertebral body centres a point distribution model was derived. The model is used as a basis to reconstruct the spinal midline from back shape data (active shape model). RESULTS: 478 rasterstereographs of 114 scoliotic patients have been evaluated with this new procedure and with an existing procedure. Both procedures deliver a three-dimensional curve of the spinal midline. The frontal projections of these spinal midlines are compared with the vertebral centres of the corresponding 478 X-rays. The active shape model improved the results as compared to the existing procedure from sigma(x)=3.4mm to sigma(x)=3.0mm. CONCLUSION: The use of the active shape model improves the overall accuracy of the spinal midline reconstructions in scoliosis from back shape data.RELEVANCE. Improvements to the accuracy and the reliability of the three-dimensional spinal reconstruction based on back shape data, can lead to an additional reduction of X-rays for patients with a scoliosis.

Artificial Intelligence↗
PubMed2004

Meiotic defects in a man with non-obstructive azoospermia: case report.

Infertile men have an increased frequency of aneuploid sperm. We have determined that decreased recombination is associated with the production of aneuploid sperm in humans. The aim of this study was to determine whether some cases of infertility are associated with decreased meiotic recombination. Analysis of the early stages of meiosis was performed in a 33-year-old man with non-obstructive azoospermia. Newly developed immunocytogenetic techniques were used to identify the synaptonemal complex (SC) in various stages of prophase. Antibodies to meiotic proteins identified the SC (SYN1/SCP3), the centromere (CREST) and recombination sites (MLH1). Only 36 meiotic spreads were recovered from the infertile man, compared with hundreds available from controls. One-third of the cells were in zygotene compared with 4% in controls, demonstrating an inability of bivalents to synapse and progress to pachytene. The infertile man had a greatly reduced frequency of recombination, with a mean of only 32.7 MLH1 foci/cell (range 1-60) compared with 46.0 (range 21-62) in control donors. A high proportion of cells (73%) contained at least one autosomal bivalent with zero MLH1 foci, compared with only 4.5% in control donors. Discontinuities in the SC were also more prevalent (68% of cells versus 26% in controls). This is the first demonstration of dramatic pachytene-stage abnormalities in an infertile man using these powerful new immunocytogenetic techniques.

Adult↗
PubMed2001

A meiotic chromosomal core consisting of cohesin complex proteins recruits DNA recombination proteins and promotes synapsis in the absence of an axial element in mammalian meiotic cells.

The behavior of meiotic chromosomes differs in several respects from that of their mitotic counterparts, resulting in the generation of genetically distinct haploid cells. This has been attributed in part to a meiosis-specific chromatin-associated protein structure, the synaptonemal complex. This complex consist of two parallel axial elements, each one associated with a pair of sister chromatids, and a transverse filament located between the synapsed homologous chromosomes. Recently, a different protein structure, the cohesin complex, was shown to be associated with meiotic chromosomes and to be required for chromosome segregation. To explore the functions of the two different protein structures, the synaptonemal complex and the cohesin complex, in mammalian male meiotic cells, we have analyzed how absence of the axial element affects early meiotic chromosome behavior. We find that the synaptonemal complex protein 3 (SCP3) is a main determinant of axial-element assembly and is required for attachment of this structure to meiotic chromosomes, whereas SCP2 helps shape the in vivo structure of the axial element. We also show that formation of a cohesin-containing chromosomal core in meiotic nuclei does not require SCP3 or SCP2. Our results also suggest that the cohesin core recruits recombination proteins and promotes synapsis between homologous chromosomes in the absence of an axial element. A model for early meiotic chromosome pairing and synapsis is proposed.

Animals↗
PubMed2001

Spectral karyotyping (SKY) of mouse meiotic chromosomes.

The spectral karyotyping procedure of in situ hybridization with chromosome-specific probes assigns a unique colour code to each of the 21 mouse mitotic chromosomes. We have adapted this procedure to meiotic prophase chromosomes, and the results show that each of the pachytene or metaphase I bivalents can be identified. This technique has the potential to recognize synaptic anomalies and chromosome-specific structural and behavioural characteristics. We confirm these potentials by the recognition of the heterologous synapsis of the X and Y chromosomes and by the variances of synaptonemal complex lengths for each of the colour-coded bivalents in eight prophase nuclei.

Animals↗
PubMed2001

The combination of SKY and specific loci detection with FISH or immunostaining.

Spectral karyotyping (SKY) represents an effective tool to detect individual chromosomes and analyze major karyotype abnormalities within an entire genome. We have tested the feasibility of combining SKY and FISH/protein detection in order to combine SKY's unique abilities with specific loci detection. Our experimental results demonstrate that various combined protocols involving SKY, FISH and immunostaining work well when proper procedures are used. This combined approach allows the tracking of key genes or targeted chromosome regions while monitoring changes throughout the whole genome. It is particularly useful when simultaneously monitoring the behavior of both protein complexes and DNA loci within the genome. The details of this methodology are described and systematically tested in this communication.

Animals↗
PubMed2001

Does functional treatment of idiopathic clubfoot reduce the indication for surgery? Call for a widely accepted rating system.

We present our experience of treatment by physiotherapy, continuous passive motion and strapping in a series of 100 clubfeet classified on a scale of severity according to Dimeglio. Twenty-five percent were good after conservative treatment, and 75% required an operation. There were no recurrences or additional procedures. Before the introduction of the functional treatment in our department, 100% required some sort of surgical intervention and 51% required an additional procedure. In comparison with the results published by Dimeglio et al., the greatest discordance is observed in grade 2 clubfeet.

Clubfoot↗
PubMed2000

Three-dimensional imaging of acetabular dysplasia: diagnostic value and impact on surgical type classification.

OBJECTIVE: To investigate the diagnostic value and the impact on surgical type classification of three-dimensional (3D) images for pre-surgical evaluation of dysplastic hips. MATERIALS AND METHODS: Three children with a different surgical type of hip dysplasia were investigated with helical computed tomography. For each patient, two-dimensional (2D) images, 3D, and a stereolithographic model of the dysplastic hip were generated. In two separate sessions, 40 medical observers independently analyzed the 2D images (session 1), the 2D and 3D images (session 2), and tried to identify the corresponding stereolithographic hip model. The influence of both image presentation (2D versus 3D images) and observer (degree of experience, radiologist versus orthopedic surgeon) were statistically analyzed. The SL model choice reflected the impact on surgical type classification. RESULTS: Image presentation was a significant factor whereas the individual observer was not. Three-dimensional images scored significantly better than 2D images (P=0.0003). Three-dimensional imaging increased the correct surgical type classification by 35%. CONCLUSION: Three-dimensional images significantly improve the pre-surgical diagnostic assessment and surgical type classification of dysplastic hips.

Acetabulum↗
PubMed1999

Bilateral Legg-Calvé-Perthes disease: different from unilateral disease?

Twenty-five patients or 50 hips with bilateral Legg-Calvé-Perthes disease were reviewed at skeletal maturity in the orthopaedic departments of Leuven, Belgium, and Montpellier, France. The two groups were very similar as to age at onset of the disease, severity of involvement, and classification at skeletal maturity. The results seem to indicate that bilateral disease runs a more severe course as compared with unilateral Legg-Calvé-Perthes disease. Eighty percent presented with a Catterall group III and IV and Herring classification B and C. Forty-eight percent rated as Stulberg 4 and 5 at skeletal maturity.

Age Distribution↗
PubMed1999

[Villonodular synovitis of the knee in a 5-year-old child. Apropos of a case].

PURPOSE OF THE STUDY: Case report of a five-year-old boy presenting with a painless swelling of the left knee with decreased range of motion. METHOD: Joint aspiration: fluid rich in red blood cells. X-ray--CT-scan--MRI: pigmented villonodular synovitis suspected. Arthroscopy with synovectomy and biopsy confirmed diagnosis. Because of remaining swelling one month after arthroscopy, intra-articular injection of triamcinolone hexacetonide gave a good result which has been maintained after 2 years. DISCUSSION: Hypothesis on etiology and pathophysiology, differential diagnosis and treatment of Pigmented villonodular synovitis are discussed based on a study of the literature. CONCLUSION: Pigmented villonodular synovitis is a rare condition in children. Association with other congenital disorders such as polyarticular localizations and family-history have been described. The diagnosis has to be proved by a biopsy. MRI seems to be the examination which gives the best information. Surgical treatment is indicated and consists of an arthroscopic synovectomy but which is often incomplete. A postoperative injection of triamcinolone hexacetonide may be the solution to avoid recurrence of Pigmented villonodular synovitis.

Administration, Topical↗
PubMed1998

Treatment of nonunion of the humerus using the Ilizarov external fixator.

Ilizarov's method of monofocal compression was used in 30 humeri with a diaphyseal pseudarthrosis. Twenty-one patients had previous surgery but had loosening of the osteosynthesis material. Nine patients initially were treated with a hanging cast, resulting in interfragmentary distraction. Fourteen nonunions were hypertrophic, and 16 were atrophic, of which six were infected. A complete circular frame was used only in the first nine patients, whereas the remaining 21 patients were treated with the modified semicircular fixator. Union was obtained in all but two patients, with an average consolidation time of 4.5 months (range, 2.5-10 months). No patient required additional bone grafting. Apart from superficial pin tract infection seen in most of the patients, three had a minor temporary sensory neurologic problem. Four patients experienced a second fracture after removal of the fixator that required a second application of an Ilizarov frame. Although similar results with regard to union are reported after plate osteosynthesis, there was no radial nerve palsy or deep infection in this series, indicating that the treatment by the Ilizarov technique is associated with less complications. The authors' findings suggest that the Ilizarov method is a reliable treatment for humeral nonunions, even after multiple previous operations or in the event of infection.

Adolescent↗
PubMed1997

A new technique for the three-dimensional study of the spine in vitro and in vivo by using a motion-analysis system.

We introduce a new method with a motion-analysis system (MAS) to study the vertebral model in vitro. Compared with the currently most accurate technique, roentgen stereophotogrammetric analysis (RSA), the difference between the RSA and the MAS is 0.12 degree +/- 1.64 degrees. An accuracy with an error of 0.08 degree +/- 1.15 degrees is determined by means of an angle gauge. Although a significant difference between the MAS and the goniometer (p = 0.04) is found around the X-axis (theta; transverse plane), it is limited to < 1 degree. The MAS provides an in-depth insight into the mechanism of the three-dimensional rotation at each vertebra in vivo. The backward inclination of the apical vertebra (AV) and forward inclination of the upper-end vertebra (UEV) around the Y-axis (phi) results in a correction of the hypokyphosis shown by the Cobb angle in the sagittal plane. The clockwise rotation of the UEV in the Z-axis (psi) leads to a reduction of the Cobb angle in the frontal plane. Additionally, the MAS as an intraoperative alternative shows different results of the derotation maneuver by the Cotrel-Dubousset instrumentation (CDI) compared with the computed tomography (CT) scan. Our method gives more direct details of the derotation not influenced by patient posture, as observed in the CT scan.

Adolescent↗
PubMed1997

Single i.v. bolus dose of ondansetron in the prevention of postoperative nausea and emesis.

In this placebo controlled, double blind multicentre study, the efficacy and safety of a single i.v. bolus dose of ondansetron 4 mg were evaluated in the prevention of postoperative nausea and vomiting (PONV), which remains one of the most unpleasant side effects experienced by patients postoperatively. The study population included patients having general anesthesia and undergoing major gynecological or elective abdominal surgery by laparoscopy. Thirty three percent of placebo-treated patients had at least one emetic episode over 24 hrs compared with 21% in the ondansetron group (p = 0.03). Forty two percent of placebo-treated patients experienced nausea in the 24 hours post-recovery period, compared to 27% of patients treated with ondansetron 4 mg (p = 0.01). Several factors appeared to be associated with an increased risk of developing PONV, namely gender (female), type of surgery (gynecological), experience of previous PONV and duration of anesthesia; the use of propofol was not a significant factor. Ondansetron was well tolerated, with no side effect being reported as a significant problem.

Adolescent↗
PubMed1996

[The interaction of actin with myosin in fast and slow muscles of the mouse].

Conformational changes of actin, during the transition of glycerinated muscle fibers of fast (EDL) and slow (SOL) mouse muscles from relaxation to rigor, were investigated by the polarized fluorescent technique. Changes in orientation and mobility of the fluorescent probe, i.e. rhodamin-phalloidin complex bound specifically to actin, testified the alteration of actin structure. The results show that during the transition of muscle fibers from relaxation to rigor the flexibility of actin filaments for EDL and SOL changes differently: increases for the former and practically does not change for the latter. The analysis of heavy myosin chains points out that SOL contains 65.43 +/- 7.26% myosin heavy chains 1 (MHC 1) and 34.57 +/- 7.26% myosin heavy chains 2A (MHC 2A). In contrast, EDL has 4.57 +/- 2.56% MHC 2A and 96.43 +/- 2.56% myosin heavy chains 2B (MHC 2B). No MHC 1 were revealed in EDL. A proposal is made that the isoformal composition of myosin heavy chains defines the character of actin-myosin interaction in slow and fast mouse muscles.

Actins↗
PubMed1996

Slipped capital femoral epiphysis: a long-term follow-up, with special emphasis on the capacities for remodeling.

We reviewed 59 hips in 44 children with slipped capital femoral epiphysis (SCFE), all treated by in situ pinning. The average clinical and radiographic follow-up was 11.4 years. Fifty-three hips (90%) were rated as either excellent or good. Osteonecrosis or chondrolysis developed in five patients. Postoperative remodeling was noted, not only by a process of local resorption and apposition of bone, but also by correction of the disturbed anatomic axes, in proportion to the severity of the slip, together with global thickening of the femoral neck. We believe that the good long-term results after in situ pinning are the consequence of this important remodeling process.

Adolescent↗